The proposed research is a program of studies of the epidemiology of the major human cancers, with the ultimate goal of developing knowledge which will lead to the prevention of these diseases. The focus of the research will be on cancer of the breast, especially in relation to patterns of metabolism of endogenous estrogens in young adult life, oral contraceptive use, and other hormonal factors. Emphasis is on the detection of early markers characteristic of increased risk of cancer of the breast, prostate and colon. Other studies are on Hodgkin's disease, bladder cancer, cancer of the pancreas, and multiple myeloma. In addition, we plan to continue to develop epidemiologic methods, particularly those methods for application in the field of cancer epidemiology. Methodologic areas of investigation include life table analysis of survival data and various aspects of significance testing and interval estimation. Using a variety of resources, the studies will employ different epidemiologic approaches including case-control studies, prospective cohort studies, and review of existing data in the Department. Many of these studies are developed on the basis of studies designed and completed in earlier years; some studies are supported for planning phase only; and others are continuations of ongoing data collection and analysis.